Packing for balanced valves



i (No Model.) I 1 HLG. HAMMETT.

PACKING FOR BALANCED VALVES.

' No. 382,300. Patented May'8, 1888.

WW Q i 4. q J T 'HIRAM G. HAMMETT, OF TROY, NEW YORK.

PACKING FOR BALANCED VALVES.

SPECIFICATION forming part of Letters Patent No. 382,300, dated May 8,1888.

Application filed December 17, 1887. Serial N0.258,146. (No model.)

To alt whom it may concern.-

Be it known that I, HIRAM G. IIAMMETT,Of Troy, county of Rensselacr, andState of New York, have invented certain new and useful Improvements inSteamPacking for Balanced Slide-Valves, of which the following is afull, clear, and exact description, reference being had to theaccompanying drawings, and to the letters of reference marked thereon.

My invention relates especially to the con struction of packingstrips,such as are employed in some forms of steam-engine valves; but myimproved packing-strip may be employed in connection with other movingvalves, whether for governing steamorany other fluid or liquid underpressure.

The object of my invention is to provide a packing-strip which, inaddition to the usual qualities or characteristics of such strips, shallpossess the further advantage that if broken or cracked or damaged inuse it will notinjure the valve or its seat,or the wearing or bearingplate, or any of the parts, and which will cost very little more thanthe ordinary forms of packings. To accomplish this object my improvementinvolves a novel and useful form of packing-strip,which will be hereinfirst fully described, and then pointed out in the claim.

In order to illustrate the construction and operation of my device, Ihave shown at Figure 1 of the accompanying drawings an isometric view ofone form of valve (a balanced steam-engine valve) on which the improvedstrip is applied. Fig. 2 is a sectional view of the valve, showing alsothe hearing or wearing plate against which the strips are held incontact,which plate is commonly known as the balance-plate. Fig. 3 is aside elevation, Fig. 4a plan, and Fig. 5 a cross-section, ofone of thepacking-strips detached from the valve,

the same being constructed in accordance with my invention and involvingmy improvements. Like letters of reference, wherever they occur,indicate corresponding parts in all the figures.

A represents a valve having the packingstrips applied therein,and B thebalance-plate, or plate against which the strips wear. The valve andplate are of the general form shown in the patent granted to Fred W.Richardson October 31, 1882, No. 266,721. In this form the stripsoperate to exclude live steam from the top of the valve, being firmlypressed against the balance-plate by steam,which finds admission beneaththe strips. This exclusion of steam balances the valve in a manner thatneed not be here explained. r

In the form shown, C C are the side strips and D D the end strips,shaped to fit channels cut for them in the top of the valve. Thebalanceplate and the valve are of cast metahand obviously all portionsof the strips exposed to any wear should be of the same metal to insureuniformity of wear and of expansion or contraction.

These packingstrips, as heretofore made, and especially the endstrips,so1netimes crack under various strains and shocks to whichsubjected, due to vertical movements of the valve, and whenso crackedthey may cock up, causing a cutting of the balance-plate, or becomedislodged from their seats, pieces entering the ports and otherwisecausing much damage before the engine can be stopped-damage which it issometimes diflicult and expensive to repair. To obviate this and to keepthe parts of the strips together with their wearing-surfaces always inline,no matter where they may be cracked or broken, and at the same timepreserve the desirable wearing qualities, I cast the strips around acentral bar or rod' of wrought metal which cannot crack or break. Thisaffords the desired permanency of the whole, and in no way interfereswiththe wearing qualities.

The strip is represented at a, and is preferably of soft iron. I havefound that merely uniting the cast metal with the wrought-metal strip orcore will not succeed unless care be taken to produce a perfect unionbetween the two qualities or kinds of metal. First polishing and thenturning the wroughtmetal strip will enable it to unite properly with thecast metal. A less perfect union may be effected after first chalkingthe wrought strip. Other methods may be adopted. In the style of valveshown the side packing-strips are not so liable to be broken as the endstrips. Under some circumstances the side strips need not be providedwith theinterior core, while under others they should be. The end piecesare made in the form of gibs, so that they will be held and at the sametime hold the others in place as the valve travels. Springs, as E, maybe placed under the strips to hold them normally against thebalance-plate.

As before intimated,the improved packingstrips may be employed in otherforms of slide- The herein-described packi ngstrip for steam and otherbalanced slide-valves, the same con- I 5 sisting of a cast-metalexterior and a wroughtnietal core united therewith, substantially in themanner and for the purposes set forth.

In testimony that I claim the foregoing I have hereunto set my hand inthe presence of two 20 witnesses.

HIRAM G. HAMMETT.

Witnesses:

JOHN BUCKLER, WORTH Oseoon.

